“There’s very good
evidence” that high-intensity interval training provides “many of the
fitness benefits of prolonged endurance training but in much less time,”
says Chris Jordan, the director of exercise physiology at the Human
Performance Institute in Orlando, Fla., and co-author of the new
article.

Work by scientists at
McMaster University in Hamilton, Ontario, and other institutions shows,
for instance, that even a few minutes of training at an intensity
approaching your maximum capacity produces molecular changes within
muscles comparable to those of several hours of running or bike riding.

Interval training,
though, requires intervals; the extremely intense activity must be
intermingled with brief periods of recovery. In the program outlined by
Mr. Jordan and his colleagues, this recovery is provided in part by a
10-second rest between exercises. But even more, he says, it’s
accomplished by alternating an exercise that emphasizes the large
muscles in the upper body with those in the lower body. During the
intermezzo, the unexercised muscles have a moment to, metaphorically,
catch their breath, which makes the order of the exercises important.

The exercises should
be performed in rapid succession, allowing 30 seconds for each, while,
throughout, the intensity hovers at about an 8 on a discomfort scale of 1
to 10, Mr. Jordan says. Those seven minutes should be, in a word,
unpleasant. The upside is, after seven minutes, you’re done.

It is not easy to squeeze in time for the gym, especially when you live
in a world expected to be in two different places all the time. This
convenient exercise routine only takes 7 minutes to complete, and it is
based on science!